How can you determine if the given lines are perpendicular?

Question

Line 1: (-1,3) and (3,-3)

Line 2: (-3,0) and (3,3)

A)determine if they have slopes with opposite values***
B)determine if they have the same slope
C)determine if the product of their slope is 1
D)determine if the product of their slope is -1

Please check my answer?

Answer 1

I'm not Ms. Sue (sorry), but your answer is correct. :)

Answer 2

Thank you for your help! (=

Answer 3

The answer is D

Answer 4

the right answer is D

Answer 5

Thanks PAT and snow, the correct answer is D.